The ankle joint involves the intersection of the tibia, the fibula and the tarsals and metatarsals. The wrist is the joint formed at the intersection of the radius, the ulna, the carpals and the metacarpals. Both of these joints are designed to allow a great deal of freedom in the movement of the relevant appendage (i.e. the hand or foot). Attendant with this relative freedom, the joint itself is somewhat unstable, and easily subjected to trauma resulting in displacement or distortion within the bones of the joint, and in harm to the bones themselves. The wrist is the most frequently injured area of the upper extremity with three fourths of wrist injuries involving a fracture of the distal radius, and/or of the radius, and the ankle is subject to similar statistics with respect to the union of the tibia, the tarsals and the metatarsals. These injuries usually present in an emergency room setting, and often involve a fall for example for the wrist, onto an outstretched hand, and for the ankle, they involve a misstep onto a foot causing a rolling of the ankle. While the past conventional wisdom has included a belief that such injuries will tend to heal sufficiently on their own, there is often a loss of function and an early onset of arthritis that can be precipitated by the misdiagnosis and improper treatment of such injuries.
The treatments known for trauma to the extremities have included external stabilization and fixation such as by plaster casts, external fixators, and orthopedic plates. Casting alone, presents the possibility of misalignment of the fragments which can lead to severe loss of function and early onset of arthritis, if the fracture is not properly reduced, and/or if the fragments do not stay in a reduced state, in particular where the patient is not compliant. External fixators have been demonstrated to have an efficacy, but are cumbersome, cosmetically unappealing, and can lead to the possibility of infection at the attachment sites.
In order to avoid the foregoing problems, surgeons often consider methods of internal fixation, which typically include wire and/or screws, and plates. One issue presented by the use of wires is that a construct is time-consuming to construct; and screws alone, often do not provide the stability required for fusion of the fragments. Plates have the benefit of providing a construct that is designed for ease of implantation, and at the same time have the disadvantage that there is a significant variety in the shape and size of individual bones. Further, in particular, the tibia and radius bones are relatively small so that individual variations are relatively more significant than in larger bones, such as the femur, the pelvis, and the humerus. Moreover, the flesh surrounding the ankle joint is particularly dense with tendons, ligaments, nerves and blood vessels all of which are less forgiving of the intrusion of a metal construct than muscle or fatty tissue. This is also true for the wrist joint, particularly on the volar (or thumb) side.